1. Field of the Invention
The present disclosure relates to a coating and developing apparatus for applying a resist to a substrate and developing the resist after exposure.
2. Description of Related Art
A semiconductor manufacturing process includes a photolithography process comprising applying a photoresist (hereinafter simply referred to as a resist) to a surface of a semiconductor wafer (hereinafter simply referred to as a wafer), exposing the resist in a predetermined pattern, and developing the exposed resist to form a resist pattern. A coating and developing apparatus for forming such a resist pattern includes a processing block having processing modules for performing various types of processing of a wafer.
The processing block is comprised of a stack of unit blocks for forming various types of coating films (e.g. resist film) and unit blocks for performing developing processing, as described e.g. in Japanese Patent Laid-Open Publication No. 2007-115831. A wafer undergoes processing in various processing modules, provided in the unit blocks, according to a predetermined sequence.
In order to meet recent demands for finer resist patterns, increased yield, etc., processing modules provided in a processing block are becoming diversified. For example, besides a resist film-forming module for applying a resist onto a substrate, such as a wafer and a developing module for supplying a developer to the substrate, a processing block may also be provide with a back surface cleaning module for cleaning the back surface of the substrate after resist coating and a liquid processing module that supplies a chemical solution onto the resist film to form an upper film over the resist film. With an increased number of diverse processing modules provided in a processing block of a coating and developing apparatus, there is a problem of how to reduce the increase in the footprint of the apparatus.
Stacking a plurality of unit blocks in a coating and developing apparatus, as described above, is effective for reducing the footprint of the apparatus. However, because a wafer is transported sequentially to the unit blocks, the operation of the entire coating and developing apparatus must be stopped when an abnormality occurs in one processing module or one unit block, or when performing maintenance of one processing module or one unit block. This significant lowers the operation efficiency of the apparatus.